El Niño Is Rapidly Intensifying, With Over 90% Odds of Becoming a Very Strong Event
On 13 August 2026, NOAA's Climate Prediction Center (CPC) reported that El Niño was strengthening and gave a greater than 90% chance that it would become a very strong event during the Northern Hemisphere's fall and winter of 2026-27. The advisory, part of the CPC's latest ENSO discussion, confirms that El Niño conditions are already present and expected to continue. An El Niño Advisory had already been in effect since the end of July 2026.
ENSO stands for the El Niño-Southern Oscillation, a climate pattern in the tropical Pacific that swings between three phases: El Niño (warmer-than-average ocean surface temperatures), La Niña (cooler-than-average), and neutral. The CPC's 13 August forecast marks a notable upward revision from its 9 August discussion, which had placed the probability of a very strong El Niño during October-December 2026 at 81%. Four days later, that figure moved above 90%.
The trajectory leading here has been months in the making. The CPC's March 2026 ENSO discussion had forecast a 62% chance of El Niño emerging during June-August 2026 and persisting through at least year-end. At that point, La Niña conditions were still present, continuing from February 2026. The swing from La Niña to a potentially very strong El Niño within roughly six months matches the rapid transition dynamics that forecasters had flagged in the spring.
The World Meteorological Organization (WMO) had been tracking the same evolution. In an April 2026 update, the WMO signaled that an El Niño event was likely to develop from mid-2026, with implications for global temperature and rainfall patterns. By its May 2026 update, the WMO set El Niño probabilities at 80% for June-August 2026, with the chance of neutral conditions diminished to 20%. A June 2026 WMO update confirmed that 80% likelihood and noted probabilities for continuation through at least November near or above typical thresholds. On 31 July 2026, the WMO reported that a strong El Niño was developing and expected to intensify during August-October 2026, with above-normal temperatures expected worldwide.
NOAA's 13 August forecast supersedes the earlier 81% probability from 9 August, and both supersede the WMO's July characterization of a "strong" event in development. The terminology matters here. A "very strong" El Niño, as defined by the Oceanic Niño Index, requires a three-month running average of sea surface temperature anomalies in the Niño 3.4 region — a specific band of the central equatorial Pacific — at or above 2.0°C above normal. The CPC's latest discussion places the odds of reaching that threshold above 90% for the upcoming fall and winter.
The broader context involves the chain of global effects that a very strong El Niño sets in motion. Warm-phase ENSO events of this magnitude reorganize atmospheric circulation patterns across the Pacific basin and beyond, shifting thunderstorm activity away from the Maritime Continent (the region around Indonesia and the Philippines) toward the central and eastern equatorial Pacific. Think of it as the planet's weather engine shifting gears: the warm water that normally pools in the western Pacific moves eastward, and the atmosphere rearranges itself accordingly. The downstream effects include altered winter precipitation across the southern United States, drought risk in the Western Pacific and parts of Australia, and temperature changes across North America and Eurasia. The WMO's July warning about above-normal temperatures worldwide intersects with the long-term warming trend, meaning El Niño's additional warming effect on global surface temperature could push seasonal anomalies higher than they would be under neutral conditions.
For commodity markets, agricultural supply chains, and disaster risk management agencies, the timing matters. The CPC's October-December target period for peak intensity lines up with the Northern Hemisphere fall harvest and the Southern Hemisphere planting season. Grain, oilseed, and tropical commodity producers in ENSO-sensitive regions will be factoring yield risk into their decisions based on these probability assessments. Energy markets also factor El Niño into winter heating demand forecasts for the Northern Hemisphere.
The forecasting confidence level also warrants attention. A probability above 90% for a very strong event in early August reflects strong agreement across both dynamical and statistical ENSO prediction systems — the two main approaches to modeling this climate pattern. The so-called spring predictability barrier, which historically degrades ENSO forecast skill for target periods beyond the boreal spring, is now well behind us. August forecasts benefit from more robust ocean-atmosphere coupling signals, including the Bjerknes feedback, a self-reinforcing loop where warmer ocean surface temperatures weaken the trade winds, which in turn warms the ocean further. This feedback tends to sustain and strengthen developing El Niño conditions through the fall and winter. The rapid upward revision between 9 and 13 August suggests that subsurface heat content and surface wind stress observations are aligning with model trajectories pointing toward peak intensity.
The 2026-27 El Niño follows a La Niña episode that persisted into early 2026, meaning the tropical Pacific has undergone a full-phase transition within a single calendar year. The WMO and NOAA are now in agreement not only on the event's existence but on its likely intensity category, though NOAA's probability for a very strong event exceeds the WMO's July characterization. The next CPC ENSO discussion, typically issued on the second Thursday of each month, will provide an updated read on whether the ocean-atmosphere system continues to reinforce the trajectory forecasters have identified.
If realized, a very strong El Niño would place the 2026-27 event among the most intense ENSO episodes in the observational record. That carries weight for farmers, energy planners, and governments alike — not because El Niño is unusual in itself, but because events of this magnitude amplify disruptions across so many regions simultaneously.
